An avid swimmer, he was delighted when he found a waterfall with a natural pool at a local sight-seeing spot. After being told by locals that the pool was deep enough for swimming, he dived in.

'My head hit a rock and immediately I lost the ability to move or feel. Being an orthopaedic surgeon, I realised at once that I had broken my neck,' he recalls.

Unable to swim to save himself, Dr Zhang was sure he would die and mentally said goodbye to his loved ones.

But colleagues saw the blood in the water and dragged Dr Zhang to safety. He was driven 90 minutes to hospital and began treatment. But an infection that travelled to his brain from his neck brought him to the brink of death. Twenty-four days after the accident, with his condition still deteriorating, Dr Zhang was flown semi-conscious to Beijing.

With a swollen face and tubes in his body, he was sent to the Intensive Care Unit ward at the China Rehabilitation Research Centre in Beijing. He stayed there for a month and his condition started to improve. But when doctors told Dr Zhang's mother he might never walk again, she collapsed in shock.

Before she went to his bedside she composed herself and the pair played out a charade in which each pretended that the extent of his injuries were not so severe, in order not to upset each other.

With tears welling up, both mother and son smiled at each other. The only thing she could say was: 'My son, you will get better soon.'

But Dr Zhang soon sank into a deep depression and refused to talk to anybody. 'I knew I would never stand up and walk again. I felt useless, I wouldn't be able to take responsibility as a son, as a father, as a husband or as a brother. I felt there was no longer any reason for me to live.'

He told his mother to find a secluded mountain and take him there to die. Immediately, she burst into tears and told him she would die too. Shocked by her response, he promised to carry on but he only sank deeper and deeper into depression.

At the end of 1997, Dr Zhang met a Japanese professor in the hospital who told him there were many successful paraplegic people in the world. She gave him a book about a quadriplegic in America called Joni Eareckson Tada. Not only was she an artist, she had also written 27 books.

He was hooked from the first page. Joni had also broken her neck in a diving accident 30 years before him. The book described how she coped with her accident and was reborn spiritually.

'It gave me hope. She became very successful with her paintings and often travelled around giving speeches to encourage other disabled people,' Dr Zhang says.

His doctor and mother persuaded him to translate the book in order to help people like himself.

Inspired by Joni, Dr Zhang's will to live grew stronger. In 2000, he joined Joni on her mission to climb the Great Wall. 'I couldn't believe Joni's mission. But in the end, we went together,' he says.

'Before, I believed a person like me would be useless, but after I translated the book and went to the Great Wall, I realised I could still be useful and help other people.

'I thought: I used to be a surgeon, I have a medical background and I want to continue helping people. Maybe I should do something with rehabilitation.'

With that, Dr Zhang came to Hong Kong to study with the help of the Hong Kong Society for Rehabilitation.

'In China, most disabled people have to stay at home because the environment is not easily accessible. Most are also quite poor,' he says. 'I was so impressed by the environment in Hong Kong. I thought, if disabled people in China could have their own self-help groups, they would be able to help each other.'

His advice to others facing misfortune: 'Just keep the faith. Strive to achieve your potential. Never give up no matter how bad things look.'